What is the author's style in A Brief History of Time by Stephen Hawking?

Stephen W. Hawking (January 8, 1942 - ) is a world-famous theoretical physicist. He holds a top professorship at the University of Cambridge and a fellowship with Gonville and Caius College. He is most noted for his work with quantum gravity and black holes, suggesting that black holes emit radiation at their event horizons. This theoretical phenomenon is now called Hawking radiation.